Class blog for Anth 249: Evolution and human disease. We will be responding to class readings and engaging with the wider network of blogs and online content on evolutionary medicine. We might also make up some fun projects along the way.

Sunday, February 24, 2013

First Respondent: To Exercise or not to Exercise, that is the question...

While reading the section readings for this week, I was very
confused. The readings included two articles: “7 Myths About Physical Activity”and “Hunter- Gatherer Energetics and Human Obesity”. “7 Myths About Physical
Activity” talked about how beneficial exercise is no matter one’s age and how
people these days are not getting enough of it. However, “Hunter-Gatherer
Energetics and Human Obesity” talked about how a recent study showed that the
total daily energy expenditure (TEE) among Hazda hunter-gatherers was not that
much different than that of Western populations. One would think that because
Hazda hunter-gatherers have to walk, gather food, hunt, etc. they would get
more physical activity, but the study showed that this was not the case. I
nodded my head while reading the first article, thinking “yeah this is so true,
I should start working out more often”, but while reading the second article,
my face was always in a “huh?” expression. It just didn’t make sense to me. The
study showed that the “Hazda were highly active and lean, with body fat
percentages on the low end of the normal healthy range for Western populations”
(Pontzer), but they had the same TEE as Westerners, who are known to be
overweight and obese. I tried to think of reasons why this might be or maybe
even something that the scientists had missed. The only reason I could think of
was this. The reason why Westerners are obsess and the Hazda are not, even
though they have the same TEE, is because of the amount of energy intake.
Westerners are probably eating so many more calories than the Hazda that even
though they have the same amount of physical activity, they are not burning it
off. While the Hazda’s physical activity is enough to keep them fit and lean,
because of the amount of calorie intake of Westerners, their physical activity
is not enough to keep them fit. Not only is the calorie intake the problem
causing obesity, but it is also true that the Western diet is probably more
consisted of fattier, unhealthy foods. I came to the conclusion that while
physical activity and exercise is very important and beneficial to our bodies,
our diet is equally as important. If one vigorously exercises but eats a lot of
junk food, there is no point.

1 comment:

Like many of the first responders had mentioned, I agree that the reasoning behind the differences in health between the Hazdas and Westerners is due not to the level of physical activity, but difference in energy intake. Today, it seems as if Westerners eat more often (not always for reasons of hunger) as well as consuming more calories each time. Therefore, if we wanted to maintain a neutral energy balance, we should be engaging in more physical activity or eating less. Though Alicia mentioned diet and exercise as equally important factors, I would argue that diet plays a larger role in achieving health in the sense of energy intake vs. expenditure. Though physical activity is important and that diet is by no means the only factor in determining one’s health, but it’s much more difficult to rely solely on exercising to maintain a neutral energy balance. You can eat a cookie in two seconds but then have to spend 30 minutes at the gym to burn that off. To me, adapting a healthy eating lifestyle and using exercise as a means of further improving one’s health, such as heart rate, brain activity, and blood flow translates to a more efficient model. It implements health from the inside out rather than attempting to undo the damages of a poor diet. Another interesting concept I am thinking about this week is the idea of purposely exercising. Gyms and recreational centers were absent in the lives of Hazdas and our ancestors; it is a fairly modern invention. It seems almost silly if you think about it, that individuals go out of their way to work their bodies when there is the possibility of physical movement in so many day to day activities. The idea of integrating physical activity into daily life can be viewed as one that is more practical (aimed at completing a task or saving time) and just as effective with lightly heart-pumping activities throughout the day. Simple but active tasks such as cleaning the house, walking to lunch, and taking the dog out reduces sedentary periods during the day while maintaining productivity. Many individuals complain they don’t have time to exercise. Perhaps making a few tweaks to their lifestyle could allow them to obtain the daily physical activity they need.